diff -r ea12a3bb4b33 -r 18b3a9a85716 rt/vm/src/test/java/org/apidesign/vm4brwsr/BytesLoader.java
--- a/rt/vm/src/test/java/org/apidesign/vm4brwsr/BytesLoader.java	Tue Feb 24 11:12:53 2015 +0100
+++ b/rt/vm/src/test/java/org/apidesign/vm4brwsr/BytesLoader.java	Fri Feb 27 18:11:54 2015 +0100
@@ -30,10 +30,9 @@
     private static final StringArray requested = new StringArray();
 
     public byte[] get(String name) throws IOException {
-        if (requested.contains(name)) {
+        if (!requested.addIfMissing(name)) {
             throw new IllegalStateException("Requested for second time: " + name);
         }
-        requested.add(name);
         byte[] arr = readClass(name);
         /*
         System.err.print("loader['" + name + "'] = [");